The present invention relates to a microcomputer with an operating system comprising a bus structure on which at least a memory, a user interface and a central processing unit are connected, wherein the microcomputer further comprises an instruction generator, connected to the operating system, provided for generating programmable logical controller's instructions (PLC-instructions), and wherein further on said bus structure at least one hardware interface is connected which cooperates with the instruction generator, which instruction generator is further provided for converting the programmable logical controller's instructions into machine codes under control of the operating system, which central processing unit is provided for converting the machine codes into execution instructions and for supplying these execution instructions via said bus structure to the hardware interface, which hardware interface is provided for converting said execution instructions into control signals.
Microcomputers and in particular personal computers (PC's) have at present a lot of application possibilities. With some applications, devices or cards, such as for example an in/output card, are connected to PC's to realise a communication between PC and peripheral apparatus, connectable to this in/output card.
Upon controlling processes, where a number of motors have for example to be controlled and where certain parameters, such as position of objects, temperature, pressure and flow rate, must be monitored, it is known to use a Programmable Logical Controller (PLC), onto which the controllable members are connected. The PLC operates with its specific computer languages, which i.a. make use of time and ladder diagrams. Computer languages are also known which are established in the IEC1131 standard. A PC is here temporarily connected to a PLC and the PLC is in its turn connected to the controllable members. The PC is here used for programming the PLC or for loading it with a program. In order to achieve this, the PC must be provided with the required software to enable programming the PLC in its turn or to load it with a program. Once the PLC is programmed, the controllable members can be controlled by this PLC. The program is herein cyclically processed by the PLC, wherein the signals are received from and transmitted to the controllable members.
A microcomputer, in particular a personal computer, is known from Control Engineering, part 42, No. 6, May 1995, pages 56-57, XP 000527106. In this article, there is referred to the use of software in combination with such a microcomputer. The hardware interface, connected to the bus structure of the microcomputer, is herein provided to be connected to at least one in/output card of the PLC. The in/output card is in its turn connected to a controllable member. The used PLC comprises thus herein, with respect to classically used PLC, no further central processing unit, but use is made of the central processing unit of the microcomputer for processing the PLC-instructions.
A drawback of this latter system is that two devices are still required, i.e. a PC for generating and processing PLC-instructions and the PLC itself for controlling the member.
The object of the invention is to configure a PC in such a manner that it is, in addition to the usual PC function, also appropriate to exert a PLC function.
To this end, said hardware interface is further provided for supplying these control signals to at least one controllable member which is connectable onto said hardware interface and for receiving data supplied by said controllable member and forward them to said instruction generator.
Since the hardware interface is provided for supplying said control signals to at least one controllable member and for receiving data from the member, it is possible to program and to control the member, for example a motor, only by means of one device, i.e. the microcomputer according to the invention, by using PLC instructions. The microcomputer according to the invention is thus a microcomputer wherein PLC functions are integrated in the architecture and are executable by means of the microcomputer itself without requiring a separate PLC.
It has to be noted that PC-cards which are connected to a PLC and which are provided for generating PLC-instructions are known. These PC-cards comprise however an own operating system and form thus in fact a PC built-in in a PLC. It is further known to incorporate PLC-cards in a PC. These PLC-cards do not form however a part of the operating system of the PC and operate essentially autonomously from the PC. In these two known operating systems, two devices are consequently again required, i.e. a PC(-card) for programming a PLC, and the PLC(-card) for transmitting and receiving signals to controllable members. The classical architecture is thus also present here again.
Further systems are known, wherein a real-time operating system with multitasking is provided for processing data, for controlling members, and the like. Programming these systems occurs by means of PLC-instructions via an external programming device. Also here, two devices are required for programming and controlling a member. Further, use is here made of a real-time operating system, which is not necessary for the invention.
The systems known hitherto thus always start from a juxtaposition of a PC with a PLC, but not from a true combination of a PC with a PLC in one device.